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Lee, O.*; 山本 慧; 埋田 真樹; Zollitsch, C. W.*; Elyasi, M.*; 吉川 貴史*; 齊藤 英治; Bauer, G. E. W.*; 紅林 秀和*
Physical Review Letters, 130(4), p.046703_1 - 046703_6, 2023/01
被引用回数：5 パーセンタイル：80.44(Physics, Multidisciplinary)We experimentally and theoretically demonstrate that nonlinear spin-wave interactions suppress the hybrid magnon-photon quasiparticle or "magnon polariton" in microwave spectra of an yttrium iron garnet film detected by an on-chip split-ring resonator. We observe a strong coupling between the Kittel and microwave cavity modes in terms of an avoided crossing as a function of magnetic fields at low microwave input powers, but a complete closing of the gap at high powers. The experimental results are well explained by a theoretical model including the three-magnon decay of the Kittel magnon into spin waves. The gap closure originates from the saturation of the ferromagnetic resonance above the Suhl instability threshold by a coherent back reaction from the spin waves.
states in 
Ni probed via two-neutron transferFlavigny, F.*; Elseviers, J.*; Andreyev, A. N.; Bauer, C.*; Bildstein, V.*; Blazhev, A.*; 他31名*
Physical Review C, 99(5), p.054332_1 - 054332_6, 2019/05
被引用回数：8 パーセンタイル：64.15(Physics, Nuclear)The Ni isotope is known for exhibiting signs of shape coexistence at very low excitation energies. In this work, carried out at REX-Isolde, CERN, the 
Ni(
,
) reaction in inverse kinematics was studied for the first time and used to assess directly the active neutrons orbitals responsible its shape coexistence. The main states populated were the 
ground state, the second state at 1604~keV, and the first excited 2 state at 2033 keV. The analysis of the differential transfer cross-sections and comparison with theoretical DWBA calculations permitted to quantify the contribution of neutron orbits below the 
=40 gap in the structure of these states. This information is essential to better understand the phenomenon of shape coexistence in the region of medium-heavy nuclei.
Pu nuclear magnetic resonance in the candidate topological insulator PuB
Dioguardi, A. P.*; 安岡 弘志*; Thomas, S. M.*; 酒井 宏典; Cary, S. K.*; Kozimor, S. A.*; Albrecht-Schmitt, T. E.*; Choi, H. C.*; Zhu, J.-X.*; Thompson, J. D.*; et al.
Physical Review B, 99(3), p.035104_1 - 035104_6, 2019/01
被引用回数：8 パーセンタイル：37.59(Materials Science, Multidisciplinary)正方晶プルトニウムボロン化合物PuB
の単結晶、および粉末試料を用いて、Pu核核磁気共鳴(NMR)実験を行なった。この化合物は、最近になって強相関電子系のトポロジカル絶縁体候補物質と考えられている。Pu核NMRスペクトルは、結晶内Pu位置の局所対称性を反映したものとなっており、NMRシフトとNMR緩和率の温度依存性は、エネルギーギャップをもつ非磁性状態にあることが示唆された。これは、密度汎関数理論計算結果とも矛盾しない。実際に観測された巨視的なギャップ状態は、本化合物がトポロジカル絶縁体候補であることを支持している。
Gepr
gs, S.*; Kehlberger, A.*; Coletta, F.*; Qiu, Z.*; Guo, E.-J.*; Schulz, T.*; Mix, C.*; Meyer, S.*; Kamra, A.*; Althammer, M.*; et al.
Nature Communications (Internet), 7, p.10452_1 - 10452_6, 2016/02
被引用回数：152 パーセンタイル：97.33(Multidisciplinary Sciences)Magnons are the elementary excitations of a magnetically ordered system. Here, we show that the spin Seebeck effect is sensitive to the complexities of the magnon spectrum. The spin Seebeck effect is caused by a thermally excited spin dynamics that is converted to a voltage by the inverse spin Hall effect at the interface to a heavy metal contact. By investigating the temperature dependence of the spin Seebeck effect in the ferrimagnet gadlinium iron garnet, with a magnetic compensation point near room temperature, we demonstrate that high-energy exchange magnons play a key role in the spin Seebeck effect.
Bottoni, S.*; Leoni, S.*; Fornal, B.*; Raabe, R.*; Rusek, K.*; Benzoni, G.*; Bracco, A.*; Crespi, F. C. L.*; Morales, A. I.*; Bednarczyk, P.*; et al.
Physical Review C, 92(2), p.024322_1 - 024322_8, 2015/08
被引用回数：21 パーセンタイル：79.49(Physics, Nuclear)An exploratory experiment was performed at REX-ISOLDE CERN to test the potential of cluster-transfer reactions at the Coulomb barrier as a mechanism to explore the structure of exotic neutron-rich nuclei. The transfer of triton and alpha particles in a reaction of a beam of 
Rb onto a 
Li target were studied through particle-
coincidence measurements. The results indicate that such cluster transfer reactions can be an efficient method to investigate the structure of neutron-rich nuclei at medium-high excitation energies and spins.
factor of the first excited 
state in 
ZnIllana, A.*; Jungclaus, A.*; Orlandi, R.; Perea, A.*; Bauer, C.*; Briz, J. A.*; Egido, J. L.*; Gernhuser, R.*; Leske, J.*; M
cher, D.*; et al.
Physical Review C, 89(5), p.054316_1 - 054316_11, 2014/05
被引用回数：11 パーセンタイル：60.34(Physics, Nuclear)The factor of the first excited state in Zn was measured using the transient-field technique in combination with Coulomb excitation. The experiment was ran at REX-ISOLDE, CERN, and the -ray perturbed angular correlations were measured using 4 triple Germanium clusters of the Miniball array. The experimental result (2
) = +0.47(14) is significant to establish the structure of the Zn isotopes near N=40. Comparison with shell-model calculations reveal that to reproduce the measured energies and B(E2) of the Zn isotopes around N=40, both the proton excitations from the 
orbit and neutron excitations into the 
and 
orbits are essential. Furthermore, beyond-mean-field calculations reveal the need to include the triaxial degree of freedom.
芳賀 芳範; Bauer, E. D.*; Tobash, P. H.*; Mitchell, J. N.*; Ayala-Valenzuela, O.*; McDonald, R. D.*; Mielke, C. H.*; Fisk, Z.
Journal of the Korean Physical Society, 63(3), p.380 - 382, 2013/08
被引用回数：3 パーセンタイル：27.27(Physics, Multidisciplinary)Fermi surface of PuIn is investigated using a flux-grown single crystals. Shubnikov-de Haas (SdH) oscillations were detected by means of the skin-depth measurement using a proximity-detector- oscillator circuit. Angular dependence of the SdH frequency which corresponds to the extremal cross-sectional area of Fermi surface agrees well with the previous magnetic susceptibility measurement using conventional field-modulation method. The SdH oscillation suddenly vanishes when the magnetic field is tilted from the cubic [111] direction.
Althammer, M.*; Meyer, S.*; 中山 裕康*; Schreier, M.*; Altmannshofer, S.*; Weiler, M.*; Huebl, H.*; Geprgs, S.*; Opel, M.*; Gross, R.*; et al.
Physical Review B, 87(22), p.224401_1 - 224401_15, 2013/06
被引用回数：416 パーセンタイル：99.41(Materials Science, Multidisciplinary)強磁性絶縁体/Ptと強磁性絶縁体/常磁性金属/Pt複合素子において、スピンHall磁気抵抗効果の定量測定を行った。強磁性絶縁体にはイットリウム鉄ガーネット,ニッケルフェライト,マグネタイトを用い、常磁性中間層には銅、金を用いた。以上により、薄い中間層にかかわらず、Pt層のスピンHall効果と逆スピンHall効果の複合によって強磁性層の磁化方向に依存した磁気抵抗効果が生じるというスピンHall磁気抵抗効果の理論の正当性が実験的に確認された。スピンHall磁気抵抗効果の理論を援用することで、4
m
のスピンミキシングコンダクタンスを持つサンプルに対して、PtのスピンHall角とスピン拡散長がそれぞれ、
nmと得られた。
studied by means of NMR/NQR techniques酒井 宏典; 栗田 伸之*; Miclea, C. F.*; Movshovich, R.*; Lee, H.-O.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*
Journal of the Physical Society of Japan, 80(Suppl.A), p.SA059_1 - SA059_3, 2011/07
La希釈効果を(Ce, La)RhIn系において核磁気共鳴(NMR/NQR)法を用いて微視的に調べた。In(1)サイトの4
スペクトル位置から、La 5%程度の希釈によって、Ceから移送される内部磁場は減少することがわかった。これは超微細結合定数が減少したことによるものと見られる。また緩和率測定から、反強磁性秩序状態において、La希釈に伴って、Laサイトに隣接するCeモーメントが局在モーメント的に振る舞っていることがわかった。
Bauer, E. D.*; Yang, Y.-F.*; Capan, C.*; Urbano, R. R.*; Miclea, C. F.*; 酒井 宏典; Ronning, F.*; Graf, M. J.*; Balatsky, A. V.*; Movshovich, R.*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 108(17), p.6857 - 6861, 2011/04
被引用回数：36 パーセンタイル：81.82(Multidisciplinary Sciences)強相関
電子系CeCoInを例に、不均一な電子状態を例示する。熱力学的物理量と核四重極共鳴測定とを組合せて超伝導状態を解析した。非磁性不純物(Y, La, Yb, Th, Hg, Sn)の置換によって、Kondo格子の不完全性に由来する『スイスチーズ』様の不均一な電子状態を作り出すことにより、局所的に超伝導を抑制できる。一般近藤格子における物理を理解するには、この不均一な電子状態を考察する必要がある。
U nuclear relaxation rates in an itinerant antiferromagnet USb
Baek, S.-H.*; Curro, N. J.*; 酒井 宏典; Bauer, E. D.*; Cooley, J. C.*; Smith, J. L.*
Physical Review B, 81(5), p.054435_1 - 054435_5, 2010/02
被引用回数：5 パーセンタイル：26.3(Materials Science, Multidisciplinary)U nuclear spin-lattice (
) and spin-spin (
) relaxation rates in the itinerant antiferromagnet USb are reported as a function of temperature in zero field. The heating effect from the intense rf pulses that are necessary for the U NMR results in unusual complex thermal recovery of the nuclear magnetization which does not allow measuring directly. By implementing an indirect method, however, we successfully extracted of the U. We find that the temperature dependence of for both U and 
Sb follows the power law (
) with the small exponent 
= 0.3 suggesting that the same relaxation mechanism dominates the on-site and the ligand nuclei, but an anomaly at 5 K was observed, possibly due to the change in the transferred hyperfine coupling on the Sb site.
